Add a new simple delay

[stellar-aria]

This is a new digital delay inspired by the generic digital delay found in just about every DAW, particularly Ableton.

Differences from the original delay:

• Simpler architecture
• Repitch occurs on modification of the delay length, not at the insertion (i.e. at playback, not at record)
• NEON acceleration throughout

[github-actions]

Test Results

106 tests  ±0   106 ✅ ±0   1s ⏱️ ±0s
 16 suites ±0     0 💤 ±0 
 16 files   ±0     0 ❌ ±0 

Results for commit 705db32. ± Comparison against base commit f70949c.

♻️ This comment has been updated with latest results.